The goal of this study is to develop noninvasive tests for screening asymptomatic males for urethral infection with Chlamydia trachomatis and Neisseria gonorrhoeae. We will use urethral swab cultures to evaluate the predictive value of methods of detecting pyuria (microscopy and leukocyte esterase tests) and antigen or DNA probes on first-catch urine (FCU) specimens. With adequate configuration of the tests we envision the FCU specimen providing the source for both screening and diagnostic tests. The strategy will be evaluated on patients seen in an STD clinic and in high risk populations. After appropriate configuration the tests will be applied in sexually active asymptomatic young men in adolescent medicine, high school and college settings. Development of such a strategy will provide a useful tool for public health officials in combatting the epidemic of sexually transmitted diseases. We need an effective approach to reducing what is currently an ignored reservoir for these infections, the asymptomatic male.